Tattooing is accomplished by injecting colored pigment into small holes made in the skin at various depths. The most common are “professional tattoos” with depth of holes approximately 2 to 2.5 mm and “amateur tattoos” with depth of holes approximately 1.5 mm. Tattoos may have a wide range of colors and are relatively permanent.
With the rapidly growing number of people who are acquiring tattoos, many may want to later have them removed. There is, therefore, a significant demand for the removal of tattoos. Tattoo removal, however, is not easily accomplished. In tattooing, pigments are injected into the dermis, the layer of skin that lies immediately beneath the approximately one millimeter thick epidermis, which is the dead, external surface layer of the skin. The injected pigments initially tend to aggregate in the upper dermis, close to the epidermis. One method of physically removing tattoos, therefore, requires abrading away the entire epidermis immediately above the tattoo pigment. This is a painful process, which usually leave the subject with significant scarring. Over time, the tattoo pigments may become encapsulated in fibroblasts and migrate deeper into the dermis so that older tattoos, while a little duller, are even more difficult to remove by abrasion.
With the advent of high power lasers, an alternative, non-abrading method of removing tattoos, which relies on thermal photoablation, became possible. In this method, the laser wavelength is chosen so that the tattoo pigment absorbs the laser light more readily than the surrounding skin. The laser pulses are then made powerful enough so that the pigment heats up sufficiently to thermally photoablate, i.e., dissociate, into small fragments. These fragments are typically transported out of the dermis by macrophages or diffusion into streams of blood and are distributed in the patient's body.
Tattoo pigments, however, cover a range of colors, including black, white, blue, red, green, and others. Dark blue-black amateur and professional tattoos usually contain amorphous carbon, graphite, India ink, and organo-metallic dyes. There has been, therefore, no single laser most suitable for tattoo removal by thermal photoablation.
Laser-based tattoo removal, therefore, has been accomplished using a variety of lasers to induce thermal photo-ablation, including, but not limited to: Q-switched Nd:Yag lasers typically operating at 1064 nanometer (1 nanometer=1 nm=1×10−9 m) or 532 nm, with 5-20 nanoseconds (1 nanosecond=1 nsec=1×10−9 sec) pulse duration; Q-switched Alexandrite lasers typically operating at 755 nm, with 100 nsec pulse duration; and Q-switched Ruby lasers typically operating at 694 nm, with 20-40 nsec pulse duration.
These lasers are collectively known as nsec-type lasers. Typically, a cream to numb the skin is applied to the patient prior to the treatment to reduce the level of pain felt during the treatment. Pulses of the laser light, typically of the order of 5 to 100 nsec, are then directed through the surface of the subject's skin and are absorbed by the tattoo pigment. The light breaks the pigment into particles by thermal photoablation. The particles are small enough to be absorbed by the body.
The principal sources of trauma in the nsec laser removal of tattoos are the heating of the skin, which causes damage similar to a second-degree burn, and the formation of highly localized shock waves in the dermis that cause undesirable tissue damage. Even with the use of numbing agents, the patient normally experiences pain during the treatments. After each treatment, the body's scavenger cells remove the particles of pigment from the treated pigmented areas. The skin and tissue damage then heals over the next several weeks, although healing time varies depending upon the size and depth of the tattoo, the procedure used and the patient's healing process. More than a dozen treatments, which can span over 1 year or more, may be necessary to complete the process. Some scarring or color variations are likely to remain.
These current laser procedures for tattoo removal are painful, expensive, rarely 100% effective, may leave permanent scarring, and typically require multiple treatments spread over a long period of time.
Because of the problems related to the prior art, improvements in tattoo and pigment removal systems and methods are needed that more completely remove tattoos, pigments, and blemishes, do not leave permanent scarring, do not cause burning, reduce or eliminate pain, and may be accomplished with fewer treatments spanning a shorter total time period.